use super::{run_command, BuilderArgs};
use crate::{config, eww_state, resolve_block, value::AttrValue};
use anyhow::*;
use gtk::{prelude::*, ImageExt};
use std::{cell::RefCell, rc::Rc};

// TODO figure out how to
// TODO https://developer.gnome.org/gtk3/stable/GtkFixed.html

//// widget definitions

pub(super) fn widget_to_gtk_widget(bargs: &mut BuilderArgs) -> Result<Option<gtk::Widget>> {
    let gtk_widget = match bargs.widget.name.as_str() {
        "box" => build_gtk_box(bargs)?.upcast(),
        "scale" => build_gtk_scale(bargs)?.upcast(),
        "progress" => build_gtk_progress(bargs)?.upcast(),
        "image" => build_gtk_image(bargs)?.upcast(),
        "button" => build_gtk_button(bargs)?.upcast(),
        "label" => build_gtk_label(bargs)?.upcast(),
        "literal" => build_gtk_literal(bargs)?.upcast(),
        "input" => build_gtk_input(bargs)?.upcast(),
        "calendar" => build_gtk_calendar(bargs)?.upcast(),
        "color-button" => build_gtk_color_button(bargs)?.upcast(),
        "expander" => build_gtk_expander(bargs)?.upcast(),
        "color-chooser" => build_gtk_color_chooser(bargs)?.upcast(),
        "combo-box-text" => build_gtk_combo_box_text(bargs)?.upcast(),
        _ => return Ok(None),
    };
    Ok(Some(gtk_widget))
}

/// attributes that apply to all widgets
/// @widget widget
/// @desc these properties apply to _all_ widgets, and can be used anywhere!
pub(super) fn resolve_widget_attrs(bargs: &mut BuilderArgs, gtk_widget: &gtk::Widget) {
    let css_provider = gtk::CssProvider::new();

    if let Ok(visible) = bargs
        .widget
        .get_attr("visible")
        .and_then(|v| bargs.eww_state.resolve_once(bargs.local_env, v)?.as_bool())
    {
        connect_first_map(gtk_widget, move |w| {
            if visible {
                w.show();
            } else {
                w.hide();
            }
        })
    }

    let on_scroll_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));
    let on_hover_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));

    resolve_block!(bargs, gtk_widget, {
        // @prop class - css class name
        prop(class: as_string) {
            let old_classes = gtk_widget.get_style_context().list_classes();
            let old_classes = old_classes.iter().map(|x| x.as_str()).collect::<Vec<&str>>();
            let new_classes = class.split(' ').collect::<Vec<_>>();
            let (missing, new) = list_difference(&old_classes, &new_classes);
            for class in missing {
                gtk_widget.get_style_context().remove_class(class);
            }
            for class in new {
                gtk_widget.get_style_context().add_class(class);
            }
        },
        // @prop valign - how to align this vertically. possible values: $alignment
        prop(valign: as_string) { gtk_widget.set_valign(parse_align(&valign)?) },
        // @prop halign - how to align this horizontally. possible values: $alignment
        prop(halign: as_string) { gtk_widget.set_halign(parse_align(&halign)?) },
        // @prop width - width of this element. note that this can not restrict the size if the contents stretch it
        prop(width: as_f64) { gtk_widget.set_size_request(width as i32, gtk_widget.get_allocated_height()) },
        // @prop height - height of this element. note that this can not restrict the size if the contents stretch it
        prop(height: as_f64) { gtk_widget.set_size_request(gtk_widget.get_allocated_width(), height as i32) },
        // @prop active - If this widget can be interacted with
        prop(active: as_bool = true) { gtk_widget.set_sensitive(active) },
        // @prop visible - visibility of the widget
        prop(visible: as_bool = true) {
            // TODO how do i call this only after the widget has been mapped? this is actually an issue,....
            if visible { gtk_widget.show(); } else { gtk_widget.hide(); }
        },
        // @prop style - inline css style applied to the widget
        prop(style: as_string) {
            gtk_widget.reset_style();
            css_provider.load_from_data(format!("* {{ {} }}", style).as_bytes())?;
            gtk_widget.get_style_context().add_provider(&css_provider, gtk::STYLE_PROVIDER_PRIORITY_APPLICATION)
        },
        // @prop onscroll - event to execute when the user scrolls with the mouse over the widget
        prop(onscroll: as_string) {
            gtk_widget.add_events(gdk::EventMask::SCROLL_MASK);
            gtk_widget.add_events(gdk::EventMask::SMOOTH_SCROLL_MASK);
            let old_id = on_scroll_handler_id.replace(Some(
                gtk_widget.connect_scroll_event(move |_, evt| {
                    run_command(&onscroll, if evt.get_delta().1 < 0f64 { "up" } else { "down" });
                    gtk::Inhibit(false)
                })
            ));
            old_id.map(|id| gtk_widget.disconnect(id));
        },
        // @prop onhover - event to execute when the user hovers over the widget
        prop(onhover: as_string) {
            gtk_widget.add_events(gdk::EventMask::ENTER_NOTIFY_MASK);
            let old_id = on_hover_handler_id.replace(Some(
                gtk_widget.connect_scroll_event(move |_, evt| {
                    run_command(&onhover, format!("{} {}", evt.get_position().0, evt.get_position().1));
                    gtk::Inhibit(false)
                })
            ));
            old_id.map(|id| gtk_widget.disconnect(id));
        }
    });
}

/// @widget !container
pub(super) fn resolve_container_attrs(bargs: &mut BuilderArgs, gtk_widget: &gtk::Container) {
    resolve_block!(bargs, gtk_widget, {
        // @prop vexpand - should this container expand vertically
        prop(vexpand: as_bool = false) { gtk_widget.set_vexpand(vexpand) },
        // @prop hexpand - should this container expand horizontally
        prop(hexpand: as_bool = false) { gtk_widget.set_hexpand(hexpand) },
    });
}

/// @widget !range
pub(super) fn resolve_range_attrs(bargs: &mut BuilderArgs, gtk_widget: &gtk::Range) {
    let on_change_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));
    gtk_widget.set_sensitive(false);
    resolve_block!(bargs, gtk_widget, {
        // @prop value - the value
        prop(value: as_f64) { gtk_widget.set_value(value)},
        // @prop min - the minimum value
        prop(min: as_f64) { gtk_widget.get_adjustment().set_lower(min)},
        // @prop max - the maximum value
        prop(max: as_f64) { gtk_widget.get_adjustment().set_upper(max)},
        // @prop onchange - command executed once the value is changes. The placeholder `{}`, used in the command will be replaced by the new value.
        prop(onchange: as_string) {
            gtk_widget.set_sensitive(true);
            gtk_widget.add_events(gdk::EventMask::ENTER_NOTIFY_MASK);
            let old_id = on_change_handler_id.replace(Some(
                gtk_widget.connect_value_changed(move |gtk_widget| {
                    run_command(&onchange, gtk_widget.get_value());
                })
            ));
            old_id.map(|id| gtk_widget.disconnect(id));

        }
    });
}

/// @widget !orientable
pub(super) fn resolve_orientable_attrs(bargs: &mut BuilderArgs, gtk_widget: &gtk::Range) {
    resolve_block!(bargs, gtk_widget, {
        // @prop orientation - orientation of the widget. Possible values: $orientation
        prop(orientation: as_string) { gtk_widget.set_orientation(parse_orientation(&orientation)?) },
    });
}

// concrete widgets

/// @widget combo-box-text
/// @desc A combo box allowing the user to choose between several items.
fn build_gtk_combo_box_text(bargs: &mut BuilderArgs) -> Result<gtk::ComboBoxText> {
    let gtk_widget = gtk::ComboBoxText::new();
    let on_change_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));
    resolve_block!(bargs, gtk_widget, {
        // @prop items - Items that should be displayed in the combo box
        prop(items: as_vec) {
            gtk_widget.remove_all();
            for i in items {
                gtk_widget.append_text(&i);
            }
        },
        // @prop onchange - runs the code when a item was selected, replacing {} with the item as a string
        prop(onchange: as_string) {
            let old_id = on_change_handler_id.replace(Some(
                gtk_widget.connect_changed(move |gtk_widget| {
                    run_command(&onchange, gtk_widget.get_active_text().unwrap_or("".into()));
                })
            ));
            old_id.map(|id| gtk_widget.disconnect(id));
        },
    });
    Ok(gtk_widget)
}
/// @widget expander extends container
/// @desc A widget that can expand and collapse, showing/hiding it's children.
fn build_gtk_expander(bargs: &mut BuilderArgs) -> Result<gtk::Expander> {
    let gtk_widget = gtk::Expander::new(None);
    resolve_block!(bargs, gtk_widget, {
    // @prop name - name of the expander
    prop(name: as_string) {gtk_widget.set_label(Some(&name));},
    // @prop expanded - sets if the tree is expanded
    prop(expanded: as_bool) { gtk_widget.set_expanded(expanded); }
    });
    Ok(gtk_widget)
}

/// @widget color-button
/// @desc A button opening a color chooser window
fn build_gtk_color_button(bargs: &mut BuilderArgs) -> Result<gtk::ColorButton> {
    let gtk_widget = gtk::ColorButtonBuilder::new().build();
    let on_change_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));
    resolve_block!(bargs, gtk_widget, {
        // @prop use-alpha - bool to whether or not use alpha
        prop(use_alpha: as_bool) {gtk_widget.set_use_alpha(use_alpha);},

        // @prop onchange - runs the code when the color was selected
        prop(onchange: as_string) {
            let old_id = on_change_handler_id.replace(Some(
                gtk_widget.connect_color_set(move |gtk_widget| {
                    run_command(&onchange, gtk_widget.get_rgba());
                })
            ));
            old_id.map(|id| gtk_widget.disconnect(id));
        }
    });

    Ok(gtk_widget)
}

/// @widget color-chooser
/// @desc A color chooser widget
fn build_gtk_color_chooser(bargs: &mut BuilderArgs) -> Result<gtk::ColorChooserWidget> {
    let gtk_widget = gtk::ColorChooserWidget::new();
    let on_change_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));
    resolve_block!(bargs, gtk_widget, {
        // @prop use-alpha - bool to wether or not use alpha
        prop(use_alpha: as_bool) {gtk_widget.set_use_alpha(use_alpha);},

        // @prop onchange - runs the code when the color was selected
        prop(onchange: as_string) {
            let old_id = on_change_handler_id.replace(Some(
                gtk_widget.connect_color_activated(move |_a, gtk_widget| {
                    run_command(&onchange, gtk_widget);
                })
            ));
            old_id.map(|id| gtk_widget.disconnect(id));
        }
    });

    Ok(gtk_widget)
}

/// @widget scale extends range
/// @desc A slider.
fn build_gtk_scale(bargs: &mut BuilderArgs) -> Result<gtk::Scale> {
    let gtk_widget = gtk::Scale::new(
        gtk::Orientation::Horizontal,
        Some(&gtk::Adjustment::new(0.0, 0.0, 100.0, 1.0, 1.0, 1.0)),
    );
    resolve_block!(bargs, gtk_widget, {
        // @prop flipped - flip the direction
        prop(flipped: as_bool) { gtk_widget.set_inverted(flipped) },

        // @prop draw-value - draw the value of the property
        prop(draw_value: as_bool = false) { gtk_widget.set_draw_value(draw_value) },
    });
    Ok(gtk_widget)
}

/// @widget progress
/// @desc A progress bar
fn build_gtk_progress(bargs: &mut BuilderArgs) -> Result<gtk::ProgressBar> {
    let gtk_widget = gtk::ProgressBar::new();
    resolve_block!(bargs, gtk_widget, {
        // @prop flipped - flip the direction
        prop(flipped: as_bool) { gtk_widget.set_inverted(flipped) },

        // @prop value - value of the progress bar (between 0-100)
        prop(value: as_f64) { gtk_widget.set_fraction(value / 100f64) },

        // @prop orientation - orientation of the progress bar. possible values: $orientation
        prop(orientation: as_string) { gtk_widget.set_orientation(parse_orientation(&orientation)?) },
    });
    Ok(gtk_widget)
}

/// @widget input
/// @desc An input field. For this to be useful, set `focusable="true"` on the window.
fn build_gtk_input(bargs: &mut BuilderArgs) -> Result<gtk::Entry> {
    let gtk_widget = gtk::Entry::new();
    let on_change_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));
    resolve_block!(bargs, gtk_widget, {
        // @prop value - the content of the text field
        prop(value: as_string) {
            gtk_widget.set_text(&value);
        },

        // @prop onchange - Command to run when the text changes. The placeholder `{}` will be replaced by the value
        prop(onchange: as_string) {
            let old_id = on_change_handler_id.replace(Some(
                gtk_widget.connect_changed(move |gtk_widget| {
                    run_command(&onchange, gtk_widget.get_text().to_string());
                })
            ));
            old_id.map(|id| gtk_widget.disconnect(id));
        }
    });
    Ok(gtk_widget)
}

/// @widget button extends container
/// @desc A button
fn build_gtk_button(bargs: &mut BuilderArgs) -> Result<gtk::Button> {
    let gtk_widget = gtk::Button::new();
    let on_click_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));
    resolve_block!(bargs, gtk_widget, {
        // @prop onclick - a command that get's run when the button is clicked
        prop(onclick: as_string) {
            gtk_widget.add_events(gdk::EventMask::ENTER_NOTIFY_MASK);
            let old_id = on_click_handler_id.replace(Some(
                gtk_widget.connect_clicked(move |_| run_command(&onclick, ""))
            ));
            old_id.map(|id| gtk_widget.disconnect(id));

        }
    });
    Ok(gtk_widget)
}

/// @widget image
/// @desc A widget displaying an image
fn build_gtk_image(bargs: &mut BuilderArgs) -> Result<gtk::Image> {
    let gtk_widget = gtk::Image::new();
    resolve_block!(bargs, gtk_widget, {
        // @prop path - path to the image file
        // @prop width - width of the image
        // @prop height - height of the image
        prop(path: as_string, width: as_i32 = 10000, height: as_i32 = 10000) {
            let pixbuf = gdk_pixbuf::Pixbuf::from_file_at_size(std::path::PathBuf::from(path), width, height)?;
            gtk_widget.set_from_pixbuf(Some(&pixbuf));
        }
    });
    Ok(gtk_widget)
}

/// @widget box extends container
/// @desc the main layout container
fn build_gtk_box(bargs: &mut BuilderArgs) -> Result<gtk::Box> {
    let gtk_widget = gtk::Box::new(gtk::Orientation::Horizontal, 0);
    resolve_block!(bargs, gtk_widget, {
        // @prop spacing - spacing between elements
        prop(spacing: as_i32 = 0) { gtk_widget.set_spacing(spacing) },
        // @prop orientation - orientation of the box. possible values: $orientation
        prop(orientation: as_string) { gtk_widget.set_orientation(parse_orientation(&orientation)?) },
        // @prop space-evenly - space the widgets evenly.
        prop(space_evenly: as_bool = true) { gtk_widget.set_homogeneous(space_evenly) },
    });
    Ok(gtk_widget)
}

/// @widget label
/// @desc A text widget giving you more control over how the text is displayed
fn build_gtk_label(bargs: &mut BuilderArgs) -> Result<gtk::Label> {
    let gtk_widget = gtk::Label::new(None);

    resolve_block!(bargs, gtk_widget, {
        // @prop text - the text to display
        // @prop limit-width - maximum count of characters to display
        prop(text: as_string, limit_width: as_i32 = i32::MAX) {
            let text = text.chars().take(limit_width as usize).collect::<String>();
            let text = unescape::unescape(&text).context(format!("Failed to unescape label text {}", &text))?;
            gtk_widget.set_text(&text);
        },
        // @prop markup - Pango markup to display
        prop(markup: as_string) {
            gtk_widget.set_markup(&markup);
        },
        // @prop wrap - Wrap the text. This mainly makes sense if you set the width of this widget.
        prop(wrap: as_bool) {
            gtk_widget.set_line_wrap(wrap)
        }
    });
    Ok(gtk_widget)
}

/// @widget literal
/// @desc A widget that allows you to render arbitrary XML.
fn build_gtk_literal(bargs: &mut BuilderArgs) -> Result<gtk::Box> {
    let gtk_widget = gtk::Box::new(gtk::Orientation::Vertical, 0);
    gtk_widget.set_widget_name("literal");

    // TODO these clones here are dumdum
    let window_name = bargs.window_name.clone();
    let widget_definitions = bargs.widget_definitions.clone();
    resolve_block!(bargs, gtk_widget, {
        // @prop content - inline Eww XML that will be rendered as a widget.
        prop(content: as_string) {
            gtk_widget.get_children().iter().for_each(|w| gtk_widget.remove(w));
            if !content.is_empty() {
                let document = roxmltree::Document::parse(&content).map_err(|e| anyhow!("Failed to parse eww xml literal: {:?}", e))?;
                let content_widget_use = config::element::WidgetUse::from_xml_node(document.root_element().into())?;
                let child_widget = super::widget_use_to_gtk_widget(
                    &widget_definitions,
                    &mut eww_state::EwwState::default(),
                    &window_name,
                    &std::collections::HashMap::new(),
                    &content_widget_use,
                )?;
                gtk_widget.add(&child_widget);
                child_widget.show();
            }
        }
    });
    Ok(gtk_widget)
}

/// @widget calendar
/// @desc A widget that displays a calendar
fn build_gtk_calendar(bargs: &mut BuilderArgs) -> Result<gtk::Calendar> {
    let gtk_widget = gtk::Calendar::new();
    let on_click_handler_id: Rc<RefCell<Option<glib::SignalHandlerId>>> = Rc::new(RefCell::new(None));
    resolve_block!(bargs, gtk_widget, {
        // @prop day - the selected day
        prop(day: as_f64) { gtk_widget.set_property_day(day as i32) },
        // @prop month - the selected month
        prop(month: as_f64) { gtk_widget.set_property_day(month as i32) },
        // @prop year - the selected year
        prop(year: as_f64) { gtk_widget.set_property_day(year as i32) },
        // @prop show-details - show details
        prop(show_details: as_bool) { gtk_widget.set_property_show_details(show_details) },
        // @prop show-heading - show heading line
        prop(show_heading: as_bool) { gtk_widget.set_property_show_heading(show_heading) },
        // @prop show-day-names - show names of days
        prop(show_day_names: as_bool) { gtk_widget.set_property_show_day_names(show_day_names) },
        // @prop show-week-numbers - show week numbers
        prop(show_week_numbers: as_bool) { gtk_widget.set_property_show_week_numbers(show_week_numbers) },
        // @prop onclick - command to run when the user selects a date. The `{}` placeholder will be replaced by the selected date.
        prop(onclick: as_string) {
            let old_id = on_click_handler_id.replace(Some(
                gtk_widget.connect_day_selected(move |w| {
                    run_command(
                        &onclick,
                        format!("{}.{}.{}", w.get_property_day(), w.get_property_month(), w.get_property_year())
                    )
                })
            ));
            old_id.map(|id| gtk_widget.disconnect(id));
        }

    });

    Ok(gtk_widget)
}

/// @var orientation - "vertical", "v", "horizontal", "h"
fn parse_orientation(o: &str) -> Result<gtk::Orientation> {
    Ok(match o {
        "vertical" | "v" => gtk::Orientation::Vertical,
        "horizontal" | "h" => gtk::Orientation::Horizontal,
        _ => bail!(
            r#"Couldn't parse orientation: '{}'. Possible values are "vertical", "v", "horizontal", "h""#,
            o
        ),
    })
}

/// @var alignment - "fill", "baseline", "center", "start", "end"
fn parse_align(o: &str) -> Result<gtk::Align> {
    Ok(match o {
        "fill" => gtk::Align::Fill,
        "baseline" => gtk::Align::Baseline,
        "center" => gtk::Align::Center,
        "start" => gtk::Align::Start,
        "end" => gtk::Align::End,
        _ => bail!(
            r#"Couldn't parse alignment: '{}'. Possible values are "fill", "baseline", "center", "start", "end""#,
            o
        ),
    })
}

fn connect_first_map<W: IsA<gtk::Widget>, F: Fn(&W) + 'static>(widget: &W, func: F) {
    // TODO it would be better to actually remove the connect_map after first map,
    // but that would be highly annoying to implement...
    let is_first_map = std::rc::Rc::new(std::cell::RefCell::new(true));
    widget.connect_map(move |w| {
        if is_first_map.replace(false) {
            func(&w);
        }
    });
}

/// Compute the difference of two lists, returning a tuple of
/// (
///   elements that where in a but not in b,
///   elements that where in b but not in a
/// ).
fn list_difference<'a, 'b, T: PartialEq>(a: &'a [T], b: &'b [T]) -> (Vec<&'a T>, Vec<&'b T>) {
    let mut missing = Vec::new();
    for elem in a {
        if !b.contains(elem) {
            missing.push(elem);
        }
    }

    let mut new = Vec::new();
    for elem in b {
        if !a.contains(elem) {
            new.push(elem);
        }
    }
    (missing, new)
}